timeline tabs and multiple sequences

The last two builds have had this bug introduced switching between sequences.  Example: I double click into a nested sequence in order to edit, then taking the mouse up to the tabs to select the master sequence, the selection tool moves the tab out of the timeline space and into another window.  
It might be related to these workspace quirks that have been popping up.  It's absolutely maddening when diving into multiple sequences, copy/pasting, navigating through nested sequences.  
I'm not sure why it's doing it and I thought it could have been a timeline setting.  However, I've only seen it happening through the last 2-3 builds.